Blast cell cooling with guided airflow

ABSTRACT

A blast cell system is provided with simple and scalable designs that prevent short cycling of air flow through any pallets in blast cells. The blast cell includes a plurality of suction channels that provide independent fluid pathways for directing the air drawn from different rows in the blast cell into the fan.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/453,834, filed Jun. 26, 2019, which isincorporated herein in its entirety.

TECHNICAL FIELD

This specification relates to technology for efficiently coolingphysical items in a blast cell.

BACKGROUND

Convective air blast freezing is a process by which freezing of itemslike foodstuffs is facilitated by flowing very cold air over the itemsvia mechanical force. Such air blast freezing can be typically used forvery large volumes of goods that are carried on pallets. Airflow ofthousands of cubic feet per minute (CFM) can be used for freezing. Blastfreezing is typically used on perishable foods (e.g., fruits and meats)geographically near their point of initial food processing. Such goodsmay then be stored for a short or long period in frozen warehouse, andthen shipped to a point close to their use, such as to a grocery storeor a warehouse operated by a particular grocer.

Such food decays largely because it includes water, which when notfrozen, is a hospitable environment for bacteria and other pathogens.Blast freezing can prevent this process and thus is employed broadly inthe food distribution industry. Blast freezing can be a large andexpensive consumer of electricity, natural gas, or other mechanismsneeded to operate chillers, fans, and other equipment required toperform such large-scale cooling.

SUMMARY

This document generally describes technology for cooling of items suchas perishable foodstuffs. Some embodiments described herein include anitem cooling system for blast freezing items. Some examples of thesystem include a blast cell system having one or more blast cells.

The blast cell system of the present disclosure provides simple andeasily scalable designs that prevent short cycling of air flow throughany pallets in different levels (e.g., rows) in blast cells. Further,the blast cell system can reduce turbulence in air circulation in theblast cells. In some examples, different levels in a blast cell areprovided with separate suction channels configured to direct the flow ofair that is pulled from the respective levels to a fan in the blastcell. The suction channels can be designed to provide independent fluidpathways that are in fluid communication with different levels in a bayspace of a blast cell, such that air flow that has passed through therespective levels is partitioned and pulled through the independentchannels to a fan that operates to draw air from the bay space in theblast cell. The suction channels can form closed-loop circulation of airthrough different levels in the bay space of the blast cell and providea vacuum cleaner effect in air circulation in the blast cell.

Some examples of the blast cell of the present disclosure include one ormore air flow guides to reduce turbulent air and enhance flow in aircirculation in the blast cell. The air flow guides include streamlinedstructures. In some examples, the air flow guides include turning vanesthat are arranged at sharp edges or corners of the blast cell to reduceturbulence thereat and provide efficient air flow. For example, theturning vanes can be arranged at a corner adjacent a cell entry and tobe in fluid communication with a plenum that passes the air pushed fromthe fan. The turning vanes are configured to be curved so that the airpassing through the turning vanes are streamlined.

In some examples, the air flow guides include a ramp that is removablyarranged between the bay space and the cell entry and provides an airstream surface that improve air flow coming into the bay space with noor little turbulence. The ramp can be installed when the blast cell isclosed with a door. The ramp can be removed to allow entry of palletswhen the blast cell is at least partially open with the door at leastpartially removed.

Particular embodiments described herein include an apparatus for coolingitems. The apparatus includes a housing, a fan, and a plurality ofchannels. The housing can define a bay space and include a plurality ofrows in the bay space. Each of the plurality of rows is configured tohold one or more pallets of items to be cooled. The fan is arranged awayfrom the bay space and configured to circulate air through the bay spacein the housing. The fan is operable to pull the air from a rearwardregion of the bay space and discharge the air toward an opposite forwardregion of the bay space. The plurality of channels is arranged betweenthe rearward region of the bay space and the fan. Each of the pluralityof channels defines a fluid pathway from a corresponding row of theplurality of rows to the fan and is configured to direct air flow fromthe rearward region of the bay space to the fan through the fluidpathway.

In some implementations, the system can optionally include one or moreof the following features. The plurality of channels can each have adrawing end adjacent the rearward region of the bay space and adischarging end adjacent the fan. The discharging end has a narrowerwidth than the drawing end. The plurality of channels can each has awidth that gradually becomes smaller from a drawing end adjacent therearward region of the bay space to an opposite discharging end adjacentthe fan. The plurality of channels can include one or more walls curvedbetween the drawing end and the discharging end.

The apparatus may further include an intake plenum having forward andrearward ends. The forward end is in communication with the forwardregion of the bay space, and the rearward end is in communication withthe rearward region of the bay space. The fan can be arranged to flowair from the rearward end of the intake plenum toward the forward end ofthe intake plenum. The plurality of section channels is arranged betweenthe rearward region of the bay space and the rearward end of the intakeplenum. The intake plenum can be arranged to be spaced apart from thebay space of the housing. The fan can be arranged adjacent the rearwardend of the intake plenum.

The apparatus may further include an air flow guide arranged at a cornerof the housing and configured to streamline the air flow at the cornerwith reduced turbulence. The air flow guide can include a plurality ofturning vanes configured to provide curved air passages at the corner.The air flow guide can include a ramp removably arranged between theforward region of the bay space and an entrance of the housing. The rampis configured to provide a surface along which the air flows.

The apparatus may further include a door configured to selectively openor close an entrance of the housing through which the items are movedinto the bay space. The entrance can be arranged closer to the forwardregion of the bay space than the rearward region of the bay space.

The plurality of section channels can be arranged at different levelsseparated by at least one shelf in the bay space. The apparatus can beconfigured as a blast freezer. The fan can be a reversible fanconfigured to direct air in either of opposite directions in thehousing.

The apparatus may further include a booster fan configured to direct airin a direction opposite to a direction of air circulated by the fan.

Particular embodiments described herein include a method for coolingitems. The method comprising providing a plurality of rows in a bayspace of a housing, each row configured to hold items to be cooled;supplying the air from an evaporator with a fan through an intakeplenum, the intake plenum configured to direct the air toward a forwardregion of the bay space; and drawing, with the fan, the air from anrearward region of the bay space through fluid pathways defined by aplurality of channels, the plurality of channels arranged between therearward region of the bay space and the fan and being in fluidcommunication with the plurality of rows, respectively.

In some implementations, the system can optionally include one or moreof the following features. The plurality of channels can each have adrawing end adjacent the rearward region of the bay space and adischarging end adjacent the fan. The discharging end has a narrowerwidth than the drawing end. The plurality of channels can each have awidth that gradually becomes smaller from a drawing end adjacent therearward region of the bay space to an opposite discharging end adjacentthe fan. The plurality of channels can include one or more walls curvedbetween the drawing end and the discharging end.

The method may further include directing the air through an air flowguide before or after the bay space. The air flow guide can include aplurality of turning vanes configured to provide curved air passages ata corner in the housing.

Particular embodiments described herein include an apparatus for coolingitems. The apparatus includes a plurality of cells arrangedside-by-side. Each cell can include a housing, an intake plenum, a fan,and a plurality of section channels. The housing defines a bay space andincludes a plurality of sections in the bay space. Each of the pluralityof bay sections is configured to hold items to be cooled. The intakeplenum can be arranged at a top side of the housing above the bay space.The intake plenum has forward and rearward ends. The forward end is incommunication with a forward region of the bay space, and the rearwardend is in communication with a rearward region of the bay space. The fancan be arranged at the top side of the housing and adjacent the rearwardend of the intake plenum. The fan is configured to circulate air throughthe bay space in the housing. The fan is operable to pull the air fromthe rearward region of the bay space and supply the air through theintake plenum toward the forward region of the bay space. The pluralityof section channels can be arranged between the rearward region of thebay space and the rearward end of the intake plenum. The plurality ofsection channels can be in fluid communication with the plurality of baysections, respectively, and configured to direct air flow from therearward region of the bay space to the rearward end of the intakeplenum.

In some implementations, the system can optionally include one or moreof the following features. The apparatus may further include anevaporator configured to cool the air upstream the fan.

The implementations described herein can provide one or more of thefollowing advantages. First, some embodiments described herein include ablast cell system the provides cooling at lower cost, higher speed, orwith greater uniformity of temperature as compared to a blast cell thatdoes not have the suction channels and/or the air flow guides. Forexample, the suction channels in the blast cell allow air to be drawnuniformly through different levels in a blast cell. The suction channelsare configured to define fluid pathways for individual levels in a blastcell and provide separate air flow through each level of the blast cell.Therefore, the air flow through one of the levels has no or littleinfluence on the air flow through the other levels. Further, the airflow drawing through the suction channels can create a vacuum effectthat promotes effective air flow through all the pellets in respectivelevels in the blast cell, regardless of how much each level is filledwith pallets of items.

Second, some embodiments described herein include a blast cell systemthat reduces turbulence in air circulation in a blast cell, therebyimproving efficiency in cooling the pellets of items. For example, theair flow guides, such as the return vanes and the ramp, are structuredto streamline the air flow and reduce turbulence that would otherwise becreated at particular regions in the blast cell, such as the corners andentrance of the blast cell.

Third, some embodiments described herein include a blast cell systemthat is easily scalable and flexible in different applications. Forexample, the suction channels and the air flow guides of the blast cellsystem are simple structures that can be easily implemented in differentsizes and numbers. Further, the suction channels and the air flow guidesneither require additional electric devices or elements, nor involvecomplex manual operation or automation.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example blast cell system.

FIG. 2 is a side perspective view of an example blast cell with one ofopposite side walls removed.

FIG. 3 is a cross-sectional perspective view of the blast cell of FIG. 2with pallets loaded.

FIG. 4 is a side cross-sectional view of the blast cell of FIG. 2.

FIG. 5 is a side perspective view of another example blast cell with anexample air flow guide.

FIG. 6 is a side cross-sectional view of yet another example blast cellwith an example air flow guide.

FIG. 7 is a flowchart of an example method for operating the blast cellsystem.

FIG. 8 is a block diagram of an example computing device which can beused to implement the systems and methods described herein.

FIG. 9 is a perspective view of an example blast cell system.

FIG. 10 is a side perspective view of an example blast cell with one ofopposite side walls removed.

FIG. 11 is a side cross-sectional view of the blast cell of FIG. 10.

FIG. 12 illustrates an example blast cell capable of reverse airflow.

FIG. 13 illustrates another example blast cell capable of reverseairflow.

FIG. 14 illustrates an example blast cell cycle.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Described below are various implementations of methods and systems forcooling (e.g., blast freezing) items such as perishable foodstuffs thathave previously been packed as groups of items onto shipping and storagepallets. The systems and techniques discussed herein provide simple andeasily scalable blast cells that prevent short cycling of air flowthrough the items in blast cells. Each blast cell can include aplurality of suction channels that provide independent fluid pathwaysfor directing the air drawn from different rows in the blast cell intothe fan.

Referring to FIG. 1, an example blast cell system 100 is configured tocool items loaded therein. Although the blast cell system 100 isprimarily described herein as a freezer, it is understood that the blastcell system 100 can be used as a chiller with or without modification.The blast cell system 100 can include one or more blast cells 102, eachconfigured to receive items and operate to cool the items loadedtherein. In the illustrated example, the blast cells 102 are arrangedside-by-side. In other examples, at least one of the blast cells 102 isarranged at a distance from an adjacent blast cell 102. Otherconfigurations are also possible.

In this example, the blast cell system 100 can be tens of feet wide andhigh, such as, for example, 10-100 feet wide and 10-50 feet high. Theblast cell system 100 can be located inside a storage building, such asin a typical warehouse, and can rest on a concrete or similar floor.

In some embodiments, the blast cells 102 are separated from each otherand structured as a standalone apparatus. For example, the blast cells102 are modularized so that the blast cells 102 are structurallyidentical or similar to each other. A desired number of blast cells 102can be installed together, such as side-by-side as illustrated in FIG.1, to provide the blast cell system 100. In other examples, the blastcell system 100 has a single space between opposite side walls 104, 106which is partitioned by one or more middle walls to create multipleblast cells 102.

In some embodiments, the blast cells 102 are operated simultaneouslyunder the same operational scheme. In other embodiments, at least one ofthe blast cells 102 is operable individually. For example, some blastcells 102 can be operated under different operational schemes from theother blast cells 102.

Referring to FIGS. 2-4, an example of the blast cell 102 is furtherdescribed. The blast cell 102 can include a housing 110, a door 120, afan 130, an air suction channel assembly 140, and an intake plenum 150.

The housing 110 has a front side 122, a rear side 125 opposite to thefront side 122, a top side 126, and an opposite bottom side 127. Thefront side 122 can provide an opening for entrance through which items90 are carried for loading or unloading. As described herein, theentrance can be selectively closed or opened with the door 120. Theblast cell 102 can be installed for operation with the bottom side 127of the housing 110 placed on the ground or other structure.

The housing 110 includes opposite side walls 118 that generally extendbetween the front and rear sides 122 and 125 and between the top andbottom sides 126 and 127. In some embodiments, the blast cell 102 isconfigured to have a narrower width between the side walls 118 of thehousing 110 than a distance (e.g., a depth) between the front and rearsides 122 and 125 or a distance (e.g., a height) between the top andbottom sides 126 and 127. Such a narrower width can improve circulationof air that generally flows in parallel with the surfaces of the sidewalls 118 by limiting air flow in non-parallel directions, e.g.,directions at angles (e.g., perpendicular) to the surfaces of the sidewalls 118.

The housing 110 defines a bay space 112 in which items 90 are loaded forcooling. As illustrated in FIG. 3, in some embodiments, the items 90 canbe stacked on pallets 92, and the pallets 92 are carried and held in thebay space 112 so that the items 90 can be cooled in the blast cell 102.The items 90, such as boxes or packages, can be stacked in multiple rowson each pallet 92, and the items 90 in adjacent rows can be spaced apartby a separator to provide a room to allow air flow between the adjacentrows of items.

In some embodiments, as illustrated in FIG. 4, the housing 110 of theblast cell 102 is configured to provide a plurality of levels 114 in thebay space 112. In the illustrated example, the plurality of levels 114are arranged to form different rows in the bay space 112. In otherembodiments, the plurality of levels 114 can be arranged in differentorientations to form, for example, different columns or differentsections defined by multiple rows and columns.

In the illustrated example, the housing 110 includes three levels (e.g.rows) 114A, 114B, and 114C (collectively 114). Each level 114 isconfigured to hold the items 90 thereon. The blast cell 102 can provideone or more structures 116 that separate the levels 114 and hold theitems 90 on the respective levels 114. For example, the structures 116can include one or more shelves on which the items 90 and/or pallets 92are placed. Other configurations of the structures 116 are alsopossible, such as flanges extending from at least one of the oppositeside walls 118 of the blast cell 102.

In some embodiments, the blast cell 102 is configured to open forloading of items into the bay space 112. For example, the blast cell 102includes the door 120 that is arranged at the front side 122 of thehousing 110. The door 120 is configured to at least partially open thefront side 122 of the housing 110 to provide an entrance 124 to the bayspace 112. The door 120 can be of various types. For example, the door120 can be configured to swing out, swing up, roll up, or slide to sideto open up the entrance 124. When the door 120 is placed, the door 120encloses the bay space 112 for cooling the items 90 loaded herein.

The door 120 is schematically illustrated as covering the front side 122of the housing 110 in FIGS. 2 and 3, and removed to open the front side122 in FIG. 4. When the door 120 is at least partially removed toprovide the entrance 124, the items 90 can be loaded at one or more ofthe levels 114. In some embodiments, a vehicle 94, such as a forklift,can enter the bay space 112 through the entrance 124 to place or removepallets 92 of items.

The blast cell 102 further includes the fan 130 configured to circulateair through the bay space 112. In some embodiments, the fan 130 canoperate to pull the air from a rearward region 162 of the bay space 112.The fan 130 can further operate to discharge the air toward a forwardregion 164 of the bay space 112 opposite to the rearward region 162.

In some embodiments, the fan 130 is arranged away from the bay space112. The fan 130 is arranged to be spaced apart from the bay space 112and not abutted with the part (e.g., a boundary wall) of the housingthat defines the bay space 112. For example, the fan 130 can be arrangedadjacent or within the intake plenum 150 that is positioned at an upperside of the housing 110.

The blast cell 102 can include a spacing structure 166 arranged betweenthe intake plenum 150 and the bay space 112. The spacing structure 166provides spacing between the intake plenum 150 and the bay space 112 sothat the intake plenum 150 is not abutted with the boundary wall of thebay space 112. The spacing structure 166 can provide an additional roomfor the suction channel assembly 140 to increase the length of itsextension from the bay space 112 toward the fan 130. Such an extendedlength of the suction channel assembly 140 between the bay space 112 andthe fan 130 allows providing streamlined curvatures in air passages andremoving sharp edges or curves throughout the suction channel assembly140 that would cause air to turn abruptly. The spacing structure 166 canbe at least partially hollow in some embodiments. Other embodiments ofthe spacing structure 166 can be configured as a solid body, or a hollowbody filled with elements or materials.

In this example, the fan 130 is located at the rear-top of the housing110 of the blast cell 102. In other implementations, the fan 130 can belocated in other positions, such as at the bottom of the blast cell 102or at one or both sides of the blast cell 102. In other embodiments,each blast cell 102 can include multiple fans, such as one at the top ofthe blast cell 102 and one at the bottom thereof.

The fan 130 can take a variety of appropriate forms, including propellerfans, axial fans, and centrifugal fans. The fan 130 can be sized toprovide the required volume of air across expected pressure drops forthe overall circulation through the blast cell 102 when it is loadedpartially and fully.

In the blast cell system 100, a plurality of fans 130 can be arrayedhorizontally adjacent to each other across the top rear corner of anarray of the blast cells 102, as illustrated in FIG. 1. The fans 130 canbe independently operated to meet different needs in different blastcells 102. For example, particular ones of the fans 130 can be turnedoff when no air circulation is needed in particular blast cells 102.

Cooling coils (e.g., evaporators) (not shown) can be placed in the blastcell 102 or adjacent to it. For example, the cooling coils can be placedagainst the upstream or downstream faces of the fan 130, or can beplaced in the intake plenum 150 or another plenum or area where the aircirculates so as to receive warmed air and provide cooled air. In otherembodiments, the cooling coils can be placed out of the main aircirculation for the blast cell 102, such as on the roof of a building,and a single bank of cooling coils can serve multiple blast cells. Insuch an instance, a pair of taps can be made into the intake plenum 150or another part of the air circulation of the blast cell 102, where onetap can draw air out of the blast cell 102, and the other can return thecooled air into the blast cell 102, so that it can blend in with themain airflow of the blast cell 102.

The fan 130 can be connected to a fan controller 170, as illustrated inFIG. 4. The fan controller 170 controls the operation of the fan 130. Insome embodiments, the fan controller 170 includes a variable-frequencydrive that varies the fan speeds as the need for different volumes ofair circulation changes. Other drive systems can be used in the fancontroller 170 in other embodiments.

Referring still to FIGS. 2-4, the blast cell 102 includes the suctionchannel assembly 140 that has a plurality of channels 141. The channels141 are arranged between the rearward region 162 of the bay space 112and the fan 130. Each of the channels 141 defines a fluid pathway 142from a level 114 in the bay space 112 toward the fan 130. The channel141 is configured to direct air flow from the rearward region 162 of thebay space 112 toward the fan 130 through the fluid pathway 142.

In some embodiments, a plurality of channels 141 are provided forrespective levels 142 in the bay space 112. In other embodiments, theblast cell 102 includes more or less channels 141 than the number oflevels 142 in the bay space 112. In yet other embodiments, the blastcell 102 can include a single channel 140 where the blast cell 102 has asingle level 114 in the bay space 112. In yet other embodiments, theblast cell 102 can include a single channel 140 for a plurality oflevels 114 in the bay space 112.

The suction channel assembly 140 extends between a drawing end 144 and adischarging end 146. The drawing end 144 is open at the rearward region162 of the bay space 112 and in fluid communication with the bay space112. The discharging end 146 is open at the rearward end 154 of theintake plenum 150 and in fluid communication with the intake plenum 150(e.g., the air inlet portion 156 thereof).

In some embodiments, the suction channel assembly 140 is arranged at therear side 125 of the housing 110. The channels 141 of the suctionchannel assembly 140 can be arranged between the rearward region 162 ofthe bay space 112 and the rearward end 154 of the intake plenum 150, andprovide air pathways 142 between the rearward region 162 of the bayspace 112 and the rearward end 154 of the intake plenum 150.

The plurality of channels 141 of the suction channel assembly 140 can beformed by providing one or more channel walls 148 in the suction channelassembly 140. The suction channel assembly 140 is configured to becurved from the drawing end 144 and the discharging end 146 to providestreamlined air flow from the drawing end 144 to the discharging end146. In some embodiments, inner and outer walls 182 and 184 of thesuction channel assembly 140 are curved outwardly (toward the rear side125 of the housing 110), and the channel walls 148 are similarly curvedoutwardly (toward the rear side 125 of the housing 110). Otherconfigurations for the walls are also possible.

In some embodiments, the suction channel assembly 140 is shaped to benarrower at the discharging end 146 (close to the fan 130) than thedrawing end 144 (close to the bay space 112) to create a funnel effect(under Bernoulli's principle), thereby increasing suction power at thedischarging end 146 close to the fan 130. In other words, the drawingend 144 is configured to be larger in dimension than the discharging end146. For example, the drawing end 144 has a neck width D1 larger than aneck width D2 of the discharging end 146. The width W of the suctionchannel assembly 140 can gradually become smaller from the neck width D1of the drawing end 144 to the neck width D2 of the discharging end 146.

The neck width D1 of the drawing end 144 can be sized to accommodate atleast a part of the height of the bay space 112. The neck width D2 ofthe discharging end 146 can be sized to be fluidly connected to the airinlet portion 156 of the intake plenum 150 before the fan 130. The neckwidth D1 can range between about 100 inches and about 500 inches in someembodiments, or between about 200 inches and about 300 inches in otherembodiments. In yet other embodiments, the neck width D1 can be about240 inches. Other sizes of the neck width D1 are also possible. The neckwidth D2 can range between about 20 inches and about 200 inches in someembodiments, or between about 30 inches and about 100 inches. In yetother embodiments, the neck width D2 can be about 48 inches. Other sizesof the neck width D2 are also possible.

Similarly, a drawing end 194 of each channel 141 is configured to belarger in dimension than a discharging end 196 of that channel 141. Forexample, the drawing end 194 of each channel 141 has a neck width D1A,D1B, or D1C larger than a neck width D2A, D2B, or D2C of the dischargingend 146 of that channel 141. The neck width D1A, D1B, or D1C of thedrawing end 144 of each channel 141 can be sized to accommodate at leastpart of the height of each level 114A, 114B, or 114C of the bay space112. The neck width D2A, D2B, or D2C of the discharging end 146 of eachchannel 141 can be sized to be fluidly connected to the air inletportion 156 of the intake plenum 150 before the fan 130. The width W1,W2, or W2 of each channel 141 can gradually become smaller from the neckwidth D1A, D1B, or D1C of the drawing end 144 to the neck width D2A,D2B, or D2C of the discharging end 146.

In some embodiments, the neck widths D1A, D1B, and D1C of the drawingends 194 of the channels 141 are identical. In other embodiments, atleast one of the neck widths D1A, D1B, and D1C of the drawing ends 194of the channels 141 is different from the other neck width(s). In someembodiments, the neck widths D2A, D2B, and D2C of the discharging ends196 of the channels 141 are identical. In other embodiments, at leastone of the neck widths D2A, D2B, and D2C of the discharging ends 196 ofthe channels 141 is different from the other neck width(s).

The neck width D1A, D1B, or D1C each can range between about 30 inchesand about 200 inches in some embodiments, or between about 70 inches and100 inches in other embodiments. In yet other embodiments, the neckwidth D1A, D1B, or D1C can be around 80 inches respectively. Other sizesof the neck width D1A, D1B, or D1C are also possible. The neck widthsD2A, D2B, and D2C each can range between about 5 inches and about 80inches in some embodiments, or between about 8 inches and 40 inches inother embodiments. In yet other embodiments, the neck width D2A, D2B,and D2C can be around 16 inches respectively. Other sizes of the neckwidth D2A, D2B, and D2C are also possible.

In embodiments where the neck width D1 of the drawing end 144 is largerthan the neck width D2 of the discharging end 146, curvatures of thewalls 182, 148, and 184 become gradually larger in an outward direction(toward the rear side 125 of the housing). For example, the outer wall184 has a curvature larger than an adjacent channel wall 148 and theinner wall 182, and a channel wall 148 located closer to the outer wall184 has a curvature larger than the adjacent channel wall 148. Theradius of curvature R3 of the inner wall 182 can range between about 20inches and about 200 inches in some embodiments, and can be about 81inches in other embodiments. The radius of curvature R4 of the firstchannel wall 148A can range between about 25 inches and about 300 inchesin some embodiments, and can be about 184 inches in other embodiments.The radius of curvature R5 of the second channel wall 148B can rangebetween about 30 inches and about 400 inches in some embodiments, andcan be about 318 inches in other embodiments. The radius of curvature R6of the outer wall 184 can range between about 35 inches and about 500inches in some embodiments, and can be about 471 inches in otherembodiments.

The smaller size of the neck width D2 of the discharging end 146 (or theneck widths D2A, D2B, and D2C of the discharging ends 196) than the neckwidth D1 of the drawing end 144 (or the neck widths D1A, D1B, and D1C ofthe drawing ends 194) increases a vacuum cleaner effect at the back ofthe fan 130 and effectively draws air from each level 114 of the bayspace 112.

Referring still to FIGS. 2-4, in some embodiments, the blast cell 102includes the intake plenum 150. The intake plenum 150 provides a conduitfor air flow between the rearward region 162 and the forward region 164of the bay space 112. The intake plenum 150 has a forward end 152 and arearward end 154. The forward end 152 can be in fluid communication withthe forward region 164 of the bay space 112, and the rearward end 154can be in fluid communication with the rearward region 162 of the bayspace 112. In some embodiments, the intake plenum 150 is arranged at thetop side 126 of the housing 110 and extends across the bay space 112. Inother embodiments, the intake plenum 150 can be arranged in differentlocations, such as at the bottom side 127 of the housing while extendingacross the bay space 112.

The intake plenum 150 can be arranged to be spaced apart from the bayspace 112. For example, the intake plenum 150 is arranged at a distancefrom the bay space 112 with the spacing structure 166 between the intakeplenum 150 and the bay space 112. In some embodiments, the spacingstructure 166 is configured to provide spacing between the intake plenum150 and the bay space 112 to allow the channels 141 to gradually extendfrom the bay space 112 and the fan 130, thereby creating streamlined airflow passage without abrupt turns into the fan 130.

The fan 130 can be arranged relative to the intake plenum 150 to createair flow from the rearward end 154 of the intake plenum 150 toward theforward end 152 of the intake plenum 150. In some embodiments, the fan130 is arranged adjacent the rearward end 154 of the intake plenum 150.For example, the fan 130 is arranged in the passage of the intake plenum150 close to the rearward end 154 that is in fluid communication withthe plurality of channels 141. In embodiments where the plurality ofchannels 141 is arranged between the rearward region 162 of the bayspace 112 and the rearward end 154 of the intake plenum 150, the fan 130operates to draw air from the rearward region 162 of the bay space 112into the rearward end 154 of the intake plenum 150 through the fluidpathways 142 defined by the channels 141. In other embodiments, the fan130 can be arranged in different locations within the intake plenum 150.

The intake plenum 150 can have an air inlet portion 156 to which air isdrawn into the intake plenum 150 at the rearward end 154. In someembodiments, the air inlet portion 156 is formed at a corner 157 wherethe rear side 125 of the housing 110 and the top side 126 of the housing110 meet. The air inlet portion 156 is fluidly connected to adischarging end 146 of the suction channel assembly 140. In someembodiments, the channel walls 148 of the suction channel assembly 140do not extend into the air inlet portion 156 as illustrated in FIG. 4.In these embodiments, the air drawn from the discharging end 146 of thesuction channel assembly 140 turns at the corner 157 and flow into thefan 130, as depicted as arrow 270 in FIG. 6. In other embodiments, thechannel walls 148 of the suction channel assembly 140 can extend intothe air inlet portion 156 to guide air flow between the suction channelassembly 140 and the fan 130 at the corner. In yet other embodiments,the channel walls 148 of the suction channel assembly 140 can extendinto the air inlet portion 156 and up to, or close to, the inlet of thefan 130 to further guide the air flow at the corner.

The intake plenum 150 can have an air outlet portion 158 to which air isdischarged from the intake plenum 150 at the forward end 152. In someembodiments, the air outlet portion 158 is formed at a corner where thefront side 122 of the housing 110 and the top side 126 of the housing110 meet. The air outlet portion 158 is fluidly connected to the forwardregion 164 of the bay space 112. The air outlet portion 158 isconfigured to direct air passing through the intake plenum 150 into theforward region 164 of the bay space 112. In some embodiments, the airoutlet portion 158 is configured to provide a curved conduit 172 withopposite inner and outer curved walls 174 and 176 to turn air flow atthe corner. As described herein, the air outlet portion 158 can includean air flow guide 250 configured to streamline air flow at the cornerand reduce turbulence.

Referring now to FIGS. 5 and 6, in some embodiments, the blast cell 102includes an air flow guide 250 configured to reduce turbulent air andenhance air circulation in the blast cell 102. The air flow guide 250can be arranged at one or more corners or sharp portions in the housing110 and configured to streamline air flow and reduce turbulence thereat.Examples of the air flow guide 250 include a turning vane assembly 252(FIGS. 5 and 6) and a ramp 254 (FIG. 6).

As illustrated in FIGS. 5 and 6, the turning vane assembly 252 isconfigured to provide one or more curved air passages at a corner in thehousing 110. In some embodiments, the turning vane assembly 252 isprovided at the air outlet portion 158 of the intake plenum 150 andconfigured to guide air flow discharging from the intake plenum 150.

The turning vane assembly 252 can include a plurality of turning vanes253 that define curved air passages. The turning vanes 253 can bedefined by one or more curved vane walls 256 arranged between the innerand outer curved walls 276 of the air outlet portion 158 of the intakeplenum 150. In some embodiments, the vane walls 256 are spaced apartequally so that the turning vanes 253 have the same width along thelengths of the turning vanes 253. In other embodiments, at least one ofthe vane walls 256 is spaced apart at a different distance. In someembodiments, the curved walls 276 and the inner and outer curved walls174 and 176 are curved at the same curvature. In other embodiments, atleast one of the curved walls 276 and the inner and outer curved walls174 and 176 is curved at a different curvature from the other walls. Theradius of curvature R1 of the inner curved wall 174 can range betweenabout 30 inches and about 200 inches in some embodiments, and can beabout 80 inches in other embodiments. The radius of curvature R2 of theouter curved wall 176 can range between about 80 inches and about 300inches in some embodiments, and can be about 130 inches in otherembodiments. The radius of curvature of the curved walls 276 can beselected to be suitable between the radii of curvature R1 and R2 of theinner and outer curved walls 174 and 176.

As illustrated in FIG. 6, the ramp 254 is configured to provide asurface along which air flows efficiently. In some embodiments, the ramp254 is provided at a lower corner 260 in the forward region 164 of thebay space 112. For example, the ramp 252 is arranged between the forwardregion 164 of the bay space 112 and the entrance 124 of the housing 110.As the lower corner 260 is positioned close to the entrance 124 of thehousing 110, the lower corner 260 forms typically a sharp angle (e.g., aright angle) which can create turbulence in air circulation. The ramp252 provides a streamlined surface 262 that promotes efficient air flowat the lower corner 260. In some embodiments, the surface 262 of theramp 252 can be curved inwardly (e.g., concave) as illustrated in FIG.6. In other embodiments, the surface 262 can be straight or curvedoutwardly (e.g., convex).

In some embodiments, the ramp 254 can be removably placed at the lowercorner 260. For example, the ramp 254 is placed at the lower corner 260when the entrance 124 is closed with the door 120. The ramp 254 isremoved from the lower corner 260 to open the entrance 124 so that theitems 90 can be freely carried through the entrance 124 by, e.g., theforklift 94 (FIG. 4).

Although not depicted, the air flow guide 250 can be provided to otherlocations in the blast cell 102 to reduce turbulence in air circulation.For example, the turning vanes 253, the ramp 254, and/or other similarfeatures can be provided at a corner in the air inlet portion 156 of theintake plenum 150 to guide air flow turning from the outlet of thesuction channel assembly 140 into the fan 130.

Referring now to FIG. 7, an example method 300 for cooling items usingthe blast cell system 100 is described. In general, the method 300involves circulating air through the items held in the bay space 112 ofthe housing 110 in efficient and effective ways. For example, the aircan be circulated by drawing the air from the bay space 112 to the fan130 through the suction channel assembly 140. The suction channelassembly 140 includes a plurality of channels 141 configured to create avacuum cleaner effect at the back of the fan 130 and prevent shortcycling of air circulation through any of the items held on differentlevels in the blast cell 102.

The method 300 can begin at operation 302 in which a blast cell 102 isprovided with a plurality of levels (e.g., rows) 114 in a bay space 112of the blast cell 102. The levels 114 can be formed by one or morevarious structures, such as shelves, flanges, and other devicesconfigured to support items from the ground.

At operation 304, the blast cell 102 is loaded with items 90. In someembodiments, items 90 are loaded with one or more pallets 92. The items90 can be of various kinds, such as meats or vegetables, which are to becooled (e.g., frozen or chilled) for storage or shipping. The pallets ofitems can be brought into place and dropped by forklifts 94 or othermechanisms. The loading can occur as a complete batch, whereby theentire cell is turned off and then opened for loading and unloading.Alternatively, it can be on a partial-batch basis, whereby a part of thebay space (e.g., a row of the bay space) is opened for loading andunloading, while the air circulates in the blast cell.

At operation 306, air circulation starts in the blast cell 102 byoperating the fan 130 to supply cooling air. In some embodiments, thecooling air is delivered through the intake plenum 150 toward the bayspace 112 where the items 90 are held in one or more of the differentlevels 114.

At operation 308, the air flow guide 250, such as the turning vaneassembly 252 and/or the ramp 254, is optionally used to direct the airbefore it reaches the bay space 112 or after it has passed through thebay space 112. For example, the turning vane assembly 252 is arranged ata corner in the blast cell 102 and can include a plurality of turningvanes 253 defining curved air passages at the corner in the blast cell102. The ramp 254 is arranged at a corner in the blast cell 102 andprovides a streamlined surface along which air flows without turbulence.

At operation 310, the air is drawn from the bay space 112 through thesuction channel assembly 140 and delivered back to the fan 130. Thesuction channel assembly 140 includes a plurality of channels 141, eachof which has the width that gradually becomes narrower from the drawingend 194 to the discharging end 196, thereby creating a funnel effect toimprove air drawing from the bay space 112.

At operation 312, the fan 130 continues to be operated until desired.The fan 130 operates to cool the items 90 to a predetermined temperatureand maintain at or around such a temperature until unloaded.

FIG. 8 is a block diagram of an example computing device 400 which canbe used to implement the systems and methods described in this document,as either a client or as a server or plurality of servers. For example,at least some of the elements in the computing device 400 can be used toimplement the fan controller 170 as described herein.

Computing device 400 includes a processor 410, memory 420, a storagedevice 430, and an input/output device 440. Each of the components 410,420, 430, and 440 are interconnected using a system bus 450. Theprocessor 410 can process instructions for execution within thecomputing device 400, including instructions stored in the memory 420 oron the storage device 430. In one implementation, the processor 410 is asingle-threaded processor. In another implementation, the processor 410is a multi-threaded processor. The processor 410 is capable ofprocessing instructions stored in the memory 420 or on the storagedevice 430 to display graphical information for a user interface on theinput/output device 440.

The memory 420 stores information within the computing device 400. Inone implementation, the memory 420 is a computer-readable medium. In oneimplementation, the memory 420 is at least one volatile memory unit. Inanother implementation, the memory 420 is at least one non-volatilememory unit.

The storage device 430 is capable of providing mass storage for thecomputing device 400. In one implementation, the storage device 430 is acomputer-readable medium. In various different implementations, thestorage device 430 can be a floppy disk device, a hard disk device, anoptical disk device, or a tape device, a flash memory or other similarsolid state memory device, or an array of devices, including devices ina storage area network or other configurations. In one implementation, acomputer program product is tangibly embodied in an information carrier.The computer program product contains instructions that, when executed,perform one or more methods, such as those described above. Theinformation carrier is a computer- or machine-readable medium, such asthe memory 420, the storage device 430, or memory on processor 410.

The input/output device 440 provides input/output operations for thesystem 400. In one implementation, the input/output device 440 includesa keyboard and/or pointing device. In another implementation, theinput/output device 440 includes a display unit for displaying graphicaluser interfaces.

The features described can be implemented in digital electroniccircuitry, or in computer hardware, firmware, software, or incombinations of them. The apparatus can be implemented in a computerprogram product tangibly embodied in an information carrier, e.g., in amachine-readable storage device for execution by a programmableprocessor; and method steps can be performed by a programmable processorexecuting a program of instructions to perform functions of thedescribed implementations by operating on input data and generatingoutput. The described features can be implemented advantageously in oneor more computer programs that are executable on a programmable systemincluding at least one programmable processor coupled to receive dataand instructions from, and to transmit data and instructions to, a datastorage system, at least one input device, and at least one outputdevice. A computer program is a set of instructions that can be used,directly or indirectly, in a computer to perform a certain activity orbring about a certain result. A computer program can be written in anyform of programming language, including compiled or interpretedlanguages, and it can be deployed in any form, including as astand-alone program or as a module, component, subroutine, or other unitsuitable for use in a computing environment.

Suitable processors for the execution of a program of instructionsinclude, by way of example, both general and special purposemicroprocessors, and the sole processor or one of multiple processors ofany kind of computer. Generally, a processor will receive instructionsand data from a read-only memory or a random access memory or both. Theessential elements of a computer are a processor for executinginstructions and one or more memories for storing instructions and data.Generally, a computer will also include, or be operatively coupled tocommunicate with, one or more mass storage devices for storing datafiles; such devices include magnetic disks, such as internal hard disksand removable disks; magneto-optical disks; and optical disks. Storagedevices suitable for tangibly embodying computer program instructionsand data include all forms of non-volatile memory, including by way ofexample semiconductor memory devices, such as EPROM, EEPROM, and flashmemory devices; magnetic disks such as internal hard disks and removabledisks; magneto-optical disks; and CD-ROM and DVD-ROM disks. Theprocessor and the memory can be supplemented by, or incorporated in,ASICs (application-specific integrated circuits).

To provide for interaction with a user, the features can be implementedon a computer having a display device such as a CRT (cathode ray tube)or LCD (liquid crystal display) monitor for displaying information tothe user and a keyboard and a pointing device such as a mouse or atrackball by which the user can provide input to the computer.

The features can be implemented in a computer system that includes aback-end component, such as a data server, or that includes a middlewarecomponent, such as an application server or an Internet server, or thatincludes a front-end component, such as a client computer having agraphical user interface or an Internet browser, or any combination ofthem. The components of the system can be connected by any form ormedium of digital data communication such as a communication network.Examples of communication networks include, e.g., a LAN, a WAN, and thecomputers and networks forming the Internet.

The computer system can include clients and servers. A client and serverare generally remote from each other and typically interact through anetwork, such as the described one. The relationship of client andserver arises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

Referring now to FIGS. 9-11, an example blast cell system 900 isdescribed. As illustrated in FIG. 9, the blast cell system 900 can beconfigured similarly to the blast cell system 100. The blast cell system900 includes one or more blast cells 902, each configured to receiveitems and operate to cool the items loaded therein. In the illustratedexample, the blast cells 902 are arranged side-by-side and split bywalls 904. For example, similarly to the blast cells 102, the blastcells 902 can be set up by installing a desired number of blast cells902 together, such as side-by-side as illustrated in FIG. 9, to providethe blast cell system 900. In other examples, at least one of the blastcells 102 is arranged at a distance from an adjacent blast cell 102, orin other suitable configurations.

The blast cell 902 can be configured similarly to the blast cell 102. Asillustrated in FIGS. 10 and 11, an example of the blast cell 902includes a housing 910, a door 920 (to open or close an entrance 924 inFIG. 9), a fan assembly 930, an air suction channel assembly 940, and anintake plenum 950, which are similar to the housing 110, the door 120,the fan 130, the air suction channel assembly 940, and the intake plenum150 of the blast cell 102.

The blast cell 902 defines a bay space 912 in the housing 910. The bayspace 912 includes an item storage area 913 in which one or more levels914 are provided, and a forward region 964 configured to permit for airto pass through before the air flows into the item storage area 913. Inthe illustrated example, the housing 910 includes three levels (e.g.,rows) 914A, 914B, and 914C (collectively 914). The blast cell 902 canprovide one or more structures 916 that separate the levels 914 and holdthe items 90 on the respective levels 914. For example, the structures916 can include one or more frames arranged and configured to provideshelves on which the items 90 and/or pallets 92 are placed. In additionor alternatively, other configurations of the structures 116 can beprovided, such as flanges for engaging or supporting the items 90 and/orpallets 92.

In this example, unlike the blast cell 102, the blast cell 902 does notinclude a spacing structure (e.g., the spacing structure 166 of theblast cell 102) between the intake plenum 950 and a bay space 912 of thehousing 910. Instead, the intake plenum 950 and the bay space 912 issplit at least partially by a channel wall 952 therebetween. Without aspacing structure, the blast cell 902 can be made in a smaller heightthan the blast cell 102.

The intake plenum 950 of the blast cell 902 has a forward end 952 thatis in fluid communication with the forward region 964 of the bay space912. The intake plenum 950 can also be configured to have the forwardend 952 being directly open to at least a portion of the item storagearea 913. For example, the forward end 952 of the intake plenum 950 hasan opening having a length L1 that extends over the forward region 964and a portion of the item storage area 913 (e.g., a portion of the toplevel 914A of the plurality of levels 914) of the bay space 912. Inother words, the channel wall 952 that divides the intake plenum 950 andthe bay space 912 has a shortened length L2 so that the opening of theforward end 952 of the intake plenum 950 is effectively large enough toexpose the intake plenum 950 over a portion of the item storage area 913(e.g., the top level 914A) of the bay space 912. The larger opening ofthe forward end 952 of the intake plenum 950 (or the shorter channelwall 952 of the intake plenum 950) can allow air to turn from the intakeplenum 950 into the item storage area 913 early and smoothly (e.g., witha larger turning radius), thereby increasing effectiveness of aircirculation.

The fan assembly 930 can be arranged relative to the intake plenum 950to create air flow from a rearward end 954 of the intake plenum 950toward the forward end 952 of the intake plenum 950. In someembodiments, the fan assembly 930 is arranged adjacent the rearward end954 of the intake plenum 950. For example, the fan assembly 930 isarranged in the passage of the intake plenum 950 close to the rearwardend 954 that is in fluid communication with the plurality of channels941. In embodiments where the plurality of channels 941 is arrangedbetween a rearward region 962 of the bay space 912 and the rearward end954 of the intake plenum 950, the fan assembly 930 operates to draw airfrom the rearward region 962 of the bay space 912 into the rearward end954 of the intake plenum 950 through fluid pathways 942 defined by thechannels 941. The fan assembly 930 can be arranged at a distance L3 froman end of the channel wall 952 near the rearward end 954 of the intakeplenum 950. The distance L3 of the fan assembly 930 can range from 0(zero) to about half of the length L2 of the channel wall 952.

The blast cell 102, 902 can be configured to have one bay section ormultiple bay sections 915, each section 915 having a single level ormultiple levels (e.g., rows) as described herein. For example, asillustrated in FIG. 3, the blast cell 102 has a single bay section 115.Alternatively, as illustrated in FIG. 10, the blast call 902 has doublebay sections 915A and 915B arranged side-by-side and open to each other,and each of the bay sections 915A and 915B has three levels 914A, 914B,and 914C. The blast cell 902 can have multiple fans 932A and 932B in thefan assembly 930, which are aligned with the multiple bay sections 915,respectively. In other implementations, the blast cell 902 can havemultiple fans in the fan assembly for a single bay section. Withmultiple bay sections 915, the blast cell can effectively have a widerwidth for increased storage and efficient loading/unloading.

As described herein, the blast cells 102, 902 can be configured invarious suitable dimensions. For example, as illustrated in FIG. 11, anentire height H1 of the blast cell 902, a height H2 of the bay space912, a height H3 a, H3 b, H3 c of each level 914A, 914B, 914C, and aheight H4 of the intake plenum 950 can be determined to meet designrequirements and/or constraints, and also provide optimal results. Inaddition, as illustrated in FIG. 10, an entire width W1 of the blastcell 902, and a width W2 a, W2 b of each bay section 915A, 915B can bedetermined to meet design requirements and/or constraints, and alsoprovide optimal results.

As illustrated in FIG. 11, the fan assembly 930 can be arranged to beraised from the surface of the channel wall 952 at a distance L4. Inaddition or alternatively, the fan assembly 930 can be arranged to abutwith the top surface of the intake plenum 950. Other arrangements of thefan assembly 930 are also possible with respect to the channel wall 952.For example, the fan assembly 930 can be arranged to be seated on thesurface of the channel wall 952 (e.g., the distance L4 is zero).

Referring now to FIGS. 12-14, an example blast cell system 1000 isdescribed for flowing air in reverse. In general, the air can besupplied through the channels 141 into the bay space 112. Such a reverseair flow may be performed at different stages of a blast cycle, such asfor a period of time in the middle of a blast cycle, near the end of ablast cycle, etc. For example, air is circulated in the direction (fromthe bay space 112 to the fan through the channels 141) described inFIGS. 1-7 and 10-11 for a majority of a blast cycle, and the air can bereversed near the end of the blast cycle. Other blast cycles are alsopossible using circulation of air in two opposite directions.

Reverse air flow can be implemented in a blast cell, such as the blastcell 250 in FIG. 6 or the blast cell 902 of FIG. 11. As illustrated inFIG. 12, the fan 130 of the blast cell 250 can be a reversible fan whichcan be controlled to blow air in a first direction D1 or in an oppositesecond direction D2.

In addition or alternatively, as illustrated in FIG. 13, the blast cell250 can include one or more booster fans 131 configured to create airflow in the second direction D2. For example, where the fan 130 is notreversible, the booster fans 131 can be used to create airflow in areverse direction while the fan 130 is turned off. Alternatively, wherethe fan 130 is reversible, the booster fans 131 can be used to augment areverse airflow while the fan 130 blows the air in the reversedirection. The booster fans 131 can be arranged in various locations.For example, the booster fans 131 can be arranged at locations in theintake plenum 150. Other locations along an airflow in a blast cell arealso possible. The booster fans 131 can be configured and sized to takeup the entire cross section of the airflow path (e.g., the entire crosssection of the intake plenum where the booster fans are located).Alternatively, the booster fans 131 can be configured and sized to besmaller than the cross section of the airflow path.

Referring to FIG. 14, an example blast cycle 1100 is described which canselectively generate airflow in either of two opposite directions. Theblast cycle 1100 can include operation (e.g., a forward airflowoperation 1102) of a fan and/or a booster fan (e.g., the fan 130, 930and/or the booster fans 131) in a first rotational direction tocirculate air in a direction (e.g., the first direction D1), operation(e.g., a reverse airflow operation 1104) of the fan and/or the boosterfan in a second rotational direction (e.g., opposite to the firstrotational direction) to circulate air in a reverse direction (e.g., thesecond direction D2), and stopping (e.g., a fan stop operation 1106) thefan and/or the booster fan.

A blast cycle 1100 can include one or more forward airflow operations1102, one or more reverse airflow operations 1104, and one or more fanstop operations 1106. The number of each of the operations 1102, 1104,and 1106 can be determined as appropriate. In some implementations, theblast cycle 1100 can include no forward airflow operation 1102, noreverse airflow operation 1104, or no fan stop operation 1106 (exceptfor ending the blast cycle). Further, one or more forward airflowoperations 1102, one or more reverse airflow operations 1104, and one ormore fan stop operations 1106 can be arranged in various sequences andwith various durations.

In some implementations, a schedule for a blast cycle can include areverse airflow operation for a predetermined period of time near theend of a blast cycle while the remaining blast cycle is operated with aforward airflow operation. In other implementations, one or more reverseairflow operations can be included intermittently throughout a blastcycle.

In some implementations, a schedule of when to forward airflow (theforward airflow operation 1102), when to reverse airflow (the reverseairflow operation 1104), and/or when to stop (the fan stop operation1106) can be determined by detecting a heat transfer coefficient at eachpallet position in the cell and running an optimization algorithm forminimizing the freeze time of the last freezing pallet. Alternatively orin addition, real-life experiments can be run with temperature probes inall pallet positions to determine an optimal airflow schedule. Inaddition or alternatively, a schedule can be determined by measuringtemperatures (e.g., using temperature sensors) and calculating atemperature differential reading. The airflow can be forwarded andreversed based on when the temperature differential value hits certainthreshold values.

The forward airflow operation 1102 can be switched to the reverseairflow operation 1104 when a first trigger condition 1110 occurs or isdetected, and the reverse airflow operation 1104 can be switched to theforward airflow operation 1102 when a second trigger condition 1112occurs or is detected. The forward airflow operation 1102 can beswitched to the fan stop operation 1106 when a third trigger condition1114 occurs or is detected, and the fan stop operation 1106 can beswitched to the forward airflow operation 1102 when a fourth triggercondition 1116 occurs or is detected. The reverse airflow operation 1104can be switched to the fan stop operation 1106 when a fifth triggercondition 1118 occurs or is detected, and the fan stop operation 1106can be switched to the reverse airflow operation 1104 when a sixthtrigger condition 1120 occurs or is detected. The trigger conditions1110, 1112, 1114, 1116, 1118, and 1120 can be predetermined based onvarious factors associated with operations of blast cells, such as time,air temperature, pallet temperature, efficiency, etc. The third andfifth trigger conditions 1114 and 1118 can include the end of a blastcycle or the end of operation of a blast cell so that the fans and blastfans in a blast cell are stopped when they don't need to be operated.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of thedisclosed technology or of what may be claimed, but rather asdescriptions of features that may be specific to particular embodimentsof particular disclosed technologies. Certain features that aredescribed in this specification in the context of separate embodimentscan also be implemented in combination in a single embodiment in part orin whole. Conversely, various features that are described in the contextof a single embodiment can also be implemented in multiple embodimentsseparately or in any suitable subcombination. Moreover, althoughfeatures may be described herein as acting in certain combinationsand/or initially claimed as such, one or more features from a claimedcombination can in some cases be excised from the combination, and theclaimed combination may be directed to a subcombination or variation ofa subcombination. Similarly, while operations may be described in aparticular order, this should not be understood as requiring that suchoperations be performed in the particular order or in sequential order,or that all operations be performed, to achieve desirable results.Particular embodiments of the subject matter have been described. Otherembodiments are within the scope of the following claims.

What is claimed is:
 1. An apparatus for cooling items, the apparatuscomprising: a housing defining a bay space and including a plurality ofrows in the bay space, each of the plurality of rows configured to holdone or more pallets of items to be cooled; at least one fan arrangedaway from the bay space and configured to circulate air through the bayspace in the housing, the at least one fan operable to pull the air froma rearward region of the bay space and discharge the air toward anopposite forward region of the bay space; a plurality of channelsarranged between the rearward region of the bay space and the at leastone fan, each of the plurality of channels defining a fluid pathway froma corresponding row of the plurality of rows to the at least one fan andconfigured to direct air flow between the rearward region of the bayspace and the at least one fan through the fluid pathway; and acontroller configured to selectively operate the at least one fan in aplurality of modes including a first operational mode and a secondoperational mode, wherein the at least one fan is configured to createair flow in a first direction in the first operational mode and in asecond direction in the second operational mode, the controllerconfigured to perform operations comprising: receiving a schedule for acooling cycle; receiving operational factors; determining a firsttrigger condition based on at least one of the schedule and theoperational factors; and switching, based on the first triggercondition, the at least one fan from the first operational mode to thesecond operational mode, wherein a third operational mode is performedbetween the first and second operational modes.
 2. The apparatus ofclaim 1, further comprising: an intake plenum having forward andrearward ends, the forward end being in communication with the forwardregion of the bay space, and the rearward end being in communicationwith the rearward region of the bay space, wherein the at least one fanis arranged to flow air from the rearward end of the intake plenumtoward the forward end of the intake plenum, wherein the plurality ofsection channels is arranged between the rearward region of the bayspace and the rearward end of the intake plenum.
 3. The apparatus ofclaim 1, further comprising: a door configured to selectively open orclose an entrance of the housing through which the items are moved intothe bay space, the entrance arranged closer to the forward region of thebay space than the rearward region of the bay space.
 4. The apparatus ofclaim 1, the apparatus is configured as a blast freezer.
 5. Theapparatus of claim 1, wherein the operations comprise: determining asecond trigger condition based on at least one of the schedule and theoperational factors; and switching, based on the second triggercondition, the at least one fan from the second operational mode back tothe first operational mode.
 6. The apparatus of claim 1, wherein theoperational factors include at least one of time, air temperature, andtemperature of the one or more pallets of items to be cooled.
 7. Theapparatus of claim 1, wherein the controller is configured to operatethe at least one fan in the second operational mode near an end of thecooling cycle after operating in the first operational mode.
 8. Theapparatus of claim 1, wherein the controller is configured to operatethe at least one fan in the second operational mode intermittentlythroughout the cooling cycle.
 9. The apparatus of claim 1, wherein theplurality of channels each has a width that gradually becomes smallerfrom a drawing end adjacent the rearward region of the bay space to anopposite discharging end adjacent the at least one fan.
 10. Theapparatus of claim 9, wherein the plurality of channels includes one ormore walls curved between the drawing end and the discharging end. 11.The apparatus of claim 1, wherein the schedule is determined based on aheat transfer coefficient at each pallet position and a cooling time ofeach pallet.
 12. The apparatus of claim 11, further comprising: aplurality of sensors positioned at each pallet position and configuredto measure a temperature of each pallet position over time.
 13. Theapparatus of claim 1, wherein the at least one fan is stopped in thethird operational mode, and wherein the controller is configured toperform operations comprising: determining a third trigger conditionbased on at least one of the schedule and the operational factors;switching, based on the third trigger condition, the at least one fanfrom the first operational mode to the third operational mode;determining a fourth trigger condition based on at least one of theschedule and the operational factors; and switching, based on the fourthtrigger condition, the at least one fan from the third operational modeback to the first operational mode.
 14. The apparatus of claim 13,wherein the controller is configured to perform operations comprising:determining a fifth trigger condition based on at least one of theschedule and the operational factors; switching, based on the fifthtrigger condition, the at least one fan from the second operational modeto the third operational mode; determining a sixth trigger conditionbased on at least one of the schedule and the operational factors; andswitching, based on the sixth trigger condition, the at least one fanfrom the third operational mode back to the second operational mode. 15.The apparatus of claim 1, wherein the first direction is opposite to thesecond direction.
 16. The apparatus of claim 15, wherein the at leastone fan is configured to, in the first operational mode, direct air flowfrom the rearward region of the bay space toward the at least one fanthrough the fluid pathway, and, in the second operational mode, directair flow from the at least one fan toward the rearward region of the bayspace through the fluid pathway.
 17. The apparatus of claim 15, whereinthe plurality of modes includes the third operational mode in which theat least one fan is stopped.
 18. The apparatus of claim 15, wherein theat least one fan includes a reversible fan configured to direct air inthe first and second directions.
 19. The apparatus of claim 15, whereinthe at least one fan includes a booster fan configured to direct air ina direction opposite to a direction of air circulated by the at leastone fan.